man voice_sweep_frequency (3): Starts a frequency sweep for a voice. Allegro game programming library.

voice_sweep_frequency(3) Starts a frequency sweep for a voice. Allegro game programming library.

SYNOPSIS

#include <allegro.h>

void voice_sweep_frequency(int voice, int time, int endfreq);

Starts a frequency sweep (glissando) from the current pitch to the specified ending pitch, lasting for time milliseconds.